Breathing mask



FIG. 1 is a perspective view of a breathing mask showing our new design;

FIG. 2 is a left side elevation thereof;

FIG. 3 is a rear perspective view thereof,

FIG. 4 is a bottom perspective view thereof; and

FIG. 5 is a right side elevation of a modified embodiment of the mask illustrated in FIG. 1.

The broken lines representing the human form is shown for illustrative purposes only. 

The ornamental design for a breathing mask, substantially as shown and described. 